#include <bits/stdc++.h>
using namespace std;
const int N = 110;
int n;
int a[N];
int main() {
  int tc;
  cin >> tc;
  while (tc--) {
    cin >> n;
    for (int i = 1; i <= n; ++i) cin >> a[i];
    vector<int> ans;
    if (n == 1) {
      if (a[1] & 1) {
      } else {
        ans.push_back(1);
      }
    } else {
      // even
      for (int i = 1; i <= n; ++i) {
        if (!(a[i] & 1)) {
          ans.push_back(i);
          break;
        }
      }
      if (!ans.size()) {
        // two odds
        for (int i = 1; i <= n; ++i) {
          if (a[i] & 1) ans.push_back(i);
          if (ans.size() == 2) break;
        }
        if (ans.size() == 1) ans.clear();
      }
    }
    if (ans.size()) {
      cout << ans.size() << endl;
      for (auto el : ans) {
        cout << el << ' ';
      }
      cout << endl;
    } else {
      cout << "-1" << endl;
    }
  }
}
